Shoe sole and process for producing thereof

ABSTRACT

A shoe sole consists of an upper sole part (1) consisting of wood, and of a running sole (7) found underneath this. The upper sole part (1) is divided in the ball region so that several narrow strips (3) are formed running crosswise to the longitudinal direction of the sole, and the strips are joined together as well as with the front and back sole parts (4, 5) by flexible intermediate pieces (6). In one form of embodiment, a reinforcing layer (8) is rigidly joined on the surface, at least in the region of strips (3) on the under side of upper sole part (1). This reinforcing layer (8) appropriately consists of at least a layer of a wood veneer, which is glued onto the under side of upper sole part (1).

BACKGROUND AND SUMMARY OF THE INVENTION

The invention concerns a shoe sole with an upper sole part consisting ofwood, whose upper side, which is preferably orthopedically shaped, formsthe support for the sole of the foot, and a running sole made of elasticand flexible material which is arranged beneath the upper sole part,whereby the upper sole part is divided, at least in the ball region,into several strips running crosswise to the lengthwise direction of thesole, and these strips are joined together by flexible intermediatepieces, preferably made of polyurethane foamed onto the wood. Further,the invention concerns a process for the manufacture of such a shoesole.

Shoe soles with an upper sole part consisting of wood and with a runningsole made of elastic and flexible material which is attached to theunder side of this upper sole part have been known for a long time. Suchshoe soles have the advantage that they have excellent support hygienicproperties, since they absorb perspiration and control moisture, andthat they support the foot in an orthopedically correct manner,particularly if the upper side of the upper sole part is shapedorthopedically. However, there is the disadvantage in shoe soles, whoseupper sole part consists wholly of wood, that its rigidity does not makepossible in such shoe soles a bending in the ball region, as isnecessary for comfortable walking.

In order to eliminate this disadvantage, it has already been proposed todivide the upper sole part consisting of wood in the ball region and toconnect the individual parts by flexible intermediate pieces,particularly of polyurethane foamed onto the wood. The arrangement ofseveral flexible intermediate pieces offers the advantage of a betterbendability. In this case, however, the strips found between theflexible intermediate pieces in the longitudinal direction of the solemust be narrow in order to be able to arrange all of the elasticintermediate pieces in the ball region. The longitudinal direction ofthe fibers of the wood runs usually in the longitudinal direction of thesole in the shoe soles, and the division of the upper sole part intostrips thus runs crosswise thereto. Now, if the individual strips arenarrow, there is the danger that with an unequal load of the same, thestrips will break along the longitudinal direction of the fibers of thewood, thus crosswise to the longitudinal direction of the strips. Suchan unequal load will occur, for example, if uneven surfaces are treadupon with the sole. Thus, if one treads upon small stones with the shoesole, this may cause the breaking of one or more strips.

Therefore, the task of the present invention is to avoid thisdisadvantage and to form a shoe sole in which the danger of breaking thenarrow strips is avoided. A solution to this task according to theinvention, proceeding from a shoe sole of the type described initially,consists of the fact that the under side of the upper sole part isjoined rigidly on the surface with a reinforcing layer at least in theregion of the strips. This reinforcing layer effects a reinforcement ofthe strips crosswise to the longitudinal direction of the fibers of thewood, as a consequence of the rigid surface combination with the underside of the upper sole part, whereby the danger of breaking is excludedeven with nonuniform loading of the sole.

According to a preferred form of embodiment of the invention, thereinforcing layer consists of at least one layer of wood veneerattached, preferably glued, to the under side, of the upper sole part.Frequently a single layer consisting of a wood veneer is sufficient forreinforcement. Sometimes, however, it is appropriate to provide severallayers, preferably joined together by gluing, whereby if there isproduced a diagonal and crosswise gluing of neighboring layers withrespect to the longitudinal directions of the fibers, a plywood isformed, which then forms the reinforcing layer. The use of such a woodveneer or such a plywood has the advantage that a solid surfaceconnection, preferably by means of gluing, can be obtained, which isnecessary for producing the aimed-at effect, as a consequence of theuniformity of the materials both for the upper sole part as well as forthe reinforcing layer.

With the use of a wood veneer as a reinforcing layer, it is of advantageif the longitudinal direction of the fibers runs perpendicular to thelongitudinal direction of the fibers of the upper sole part consistingof wood, at least for one of the layers of wood veneer, since then thereinforcement of the individual strips is produced particularly in anydirection in which there is a danger of breaking. If a single layer isprovided of a wood veneer, then the longitudinal direction of the fibersof this single layer is to be arranged perpendicular to the longitudinaldirection of the fibers of the upper sole part consisting of wood. Withthe use of plywood, which is formed, for example, from three diagonaland cross-glued layers of a wood veneer, it is appropriate to allow thelongitudinal direction of the fibers of the two outer layers to runperpendicular to the longitudinal direction of the fibers of the uppersole part consisting of wood and to allow the middle layer to runcrosswise thereto.

However, the reinforcing layer may also consist of a plastic partattached by the surface to the under side of the upper sole part. In thesimplest case, the reinforcing layer is formed by a plastic foil gluedonto the under side of the upper sole part. However, a hardenable, butnot yet hardened plastic material, for example, can be coated onto theunder side of the upper sole part, for example, by means of spraying orapplying with a spatula, and this forms the reinforcing layer afterhardening.

The reinforcing layer may also extend over any region of the under sideof the upper sole part, in which the intermediate pieces are arranged.However, it is appropriate, if the surface of the under side of theupper sole part formed by the intermediate pieces does not have thereinforcing layer. In this case, since this is particularly appropriatefor a simple manufacture of the sole of the invention, the intermediatepieces and the running sole are formed in one piece, since then thereinforcing layer does not form a separation between the intermediatepieces and the running sole.

Another solution to the task of the invention, proceeding from a shoesole of the type described initially, consists of forming the stripsfrom at least two parts, whose neighboring front surfaces essentiallyrun in the longitudinal direction of the sole and are also joinedtogether by flexible intermediate pieces. In this way, a shoe sole isformed in which the strips can be bent crosswise to their longitudinaldirection, thus as a rule in the longitudinal direction of the fibers ofthe upper sole part consisting of wood, so that in this case also, thedanger of breaking these strips with an uneven load is eliminated. It isappropriate, if all of the intermediate pieces are formed in one pieceand are thus joined together, so that a good cohesion is also assuredbetween the individual intermediate pieces, and the manufacture of theshoe sole of the invention is simplified.

The process of the invention for manufacturing the described shoe soleessentially consists of the fact that after a reinforcing layer isrigidly joined on the surface, preferably by gluing or with an adhesive,to the under side of a wood piece forming the upper sole part, at leastin the ball region, several cuts are produced in this under side in theball region, for example, by milling, by means of which in the presenceof a reinforcing layer, this is layer fully separated and the wood pieceforming the upper sole part is at least partially separated, such thatthis wood piece, if necessary with the reinforcing-layer segments joinedrigidly therewith, is inserted into a mold, that a liquid plasticmaterial, preferably a material forming polyurethane, is introducedhereon in the mold, and solidifies, particularly by foaming out, wherebyin the region of the cuts, the intermediate pieces and the running solethus formed in one piece are formed, and that finally the sole part thusmanufactured is removed from the mold. The wood piece forming the uppersole part thus need not have the exact [final] form of the upper solepart, but may also be larger; particularly, it may have a greaterthickness measured perpendicularly to the upper side of the sole. Inthis case it is possible to incompletely separate the wood piece formingthe upper part of the sole, while a joining is retained on the upperside, whereby the insertion into the mold is essentially simplified.According to another feature of the process of the invention, afterdemolding, at least the upper side of the wood piece forming the uppersole part is processed, preferably by milling or grinding, and removingexcess material, whereby not only the orthopedic shaping of this upperside can be achieved, but also any region can be eroded in which thereis still present a joining of the wood part forming the upper sole part,and thus the intermediate pieces reach to the upper side of the uppersole part.

BRIEF DESCRIPTION OF THE DRAWINGS

The shoe sole according to the invention will be explained on the basisof an example of embodiment shown schematically in the drawing.

FIG. 1 shows a top view onto a first form of embodiment of the shoe soleof the invention and

FIG. 2 represents a section along line II--II in FIG. 1.

FIG. 3 shows a top view of a second form of embodiment of the shoe soleof the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The shoe sole of the invention has an upper sole part 1 consisting ofwood, whose orthopedically shaped upper side 2 forms the support for thesole of the foot. In the ball region, the upper sole part 1 is dividedinto several strips 3 running crosswise to the longitudinal section ofthe sole, and these strips are joined together and to the adjacentsections 4, 5 by flexible intermediate pieces 6. The flexibleintermediate pieces 6 preferably consist of polyurethane, which isfoamed onto parts 3, 4, 5 consisting of wood, whereby a permanentconnection is produced between the wood parts and the flexibleintermediate pieces 6.

Underneath upper sole part 1 is found a running sole 7 of elastic andflexible material, which is formed in one piece with intermediate pieces6 and preferably also consists of polyurethane foamed onto the wood.

Since the bending capacity of the sole must be produced in the ballregion, strips 3 must be arranged at least in the ball region. Strips 3are thus viewed as narrow in the longitudinal direction of the sole,which is visible from the drawing. Since the longitudinal fibers usuallyrun in the longitudinal direction of the sole in wood soles, with anuneven loading of the sole, for example as occurs on walking on unevenground, there is the danger that the strips break along a longitudinalfiber. In order to eliminate this danger, in the form of embodimentaccording to FIGS. 1 and 2, a reinforcing layer 8 is joined rigidly tothe surface of the strips on the under side of the strips. As a resultof the simplification of manufacture of the shoe sole of the invention,since this reinforcing layer 8 is preferably introduced before the uppersole part 1 consisting of wood is separated in order to form theintermediate spaces which take up the intermediate pieces 6, it isappropriate if this reinforcing layer is extended at 8' also over aregion of approximately 1 cm beyond the limiting part of the upper frontsole part 4 and the upper back sole part 5, since in this case it isassured that, in any case, after the manufacture of the intermediatespaces taking up intermediate pieces 6, the lower sides of strips 3 arecompletely covered by reinforcing layes. Reinforcing layer 8 may alsoextend, however, proceeding from the tip of the sole, over the entireunder side of the upper front sole part.

In a particularly advantageous form of embodiment, reinforcing layer 8is formed of at least one layer of wood veneer glued onto the under sideof the upper sole part. Frequently, a single such layer is sufficient.If several layers of a wood veneer glued together are provided, thenthese are glued preferably diagonally and crosswise with respect to thelongitudinal direction of their fibers, so that a plywood is formed.With the use of a single layer of a wood veneer, the longitudinaldirection of the fibers of the same will run crosswise to thelongitudinal direction of the fibers of the upper sole part 1 consistingof wood. In case a plywood is used, it is of advantage if at least thelongitudinal direction of the fibers of some of the layers of woodveneer, and, in fact, preferably the outer layers of wood veneer, runperpendicularly to the longitudinal direction of the fibers of the uppersole part 1 consisting of wood.

Reinforcing layer 8, however, may also be formed by a plastic foilattached by adhesive to the under side of the upper sole part 1 or maybe formed of a plastic material which can be hardened and is introducedonto the under side of the upper sole part, for example, by applyingwith a spatula or spraying. Finally, it is possible to form reinforcinglayer 8 of a textile material, preferably reinforced with plastic, andattached to the under side of the upper sole part. This textile materialmay consist, for example, of a nonwoven fabric, which is impregnatedwith plastic material. A plastic material may find use, which issoftened by the introduction of heat, so that reinforcing layer 8consisting partially of a plastic material may then be adapted to theshape of the under side of upper sole part 1 and retains this form aftercooling. Glass fibers are preferably used as the base material for thetextile material.

In the manufacture of the sole of the invention, it is appropriate tostart with a wood piece whose thickness, measured perpendicularly to theupper side of the upper sole part 1, is greater than the thickness ofthe upper sole part of the finished sole. After producing the rigidsurface connection between reinforcing layer 8 and this wood piece, thewood piece is separated only partially in those places where theintermediate pieces are arranged with respect to reinforcing layer 8joined therewith, proceeding from this reinforcing layer, so that on theside lying opposite the reinforcing layer, the wood piece remainsjoined. In this way, the insertion into a mold is simplified, in whichthe intermediate pieces 6 and the running sole 7 are formed byintroducing an elastic and flexible material. After demolding, part 9 inthe region of upper side 2 of upper sole part 1, depicted in FIG. 2 bythe broken line, is removed by milling or grinding, so that thenintermediate pieces 6 reach to upper surface 2, and the necessarybending capacity is provided. Although an embodiment is shown in FIG. 2,in which the entire upper surface 2 of the upper sole part 1 isprocessed after demolding, it is also possible to endow the finalshaping to the back part of the upper side of upper sole part 1 and toonly process the front part of upper side 1 of upper sole part 1 afterdemolding, and in this way to remove any part of the wood, so as touncover the intermediate pieces 6.

The form of embodiment according to FIG. 3 is distinguished from theform of embodiment according to FIGS. 1 and 2 by the fact thatreinforcing layer 8 is omitted. In order to eliminate the danger ofbreaking of strips 3, in this form of embodiment, strips 3 consist of atleast two parts, 3, 3", whereby the division runs essentially in thelongitudinal direction of the sole. The front surfaces 10 of individualparts 3', 3" which are adjacent to each other are also joined togetherby flexible intermediate pieces 11, which operate such that the stripscan bend crosswise to their longitudinal direction, so that in this casea breaking of the strips is prevented. Flexible intermediate pieces 11may be arranged only in the region of strips 3, but also beyond thestrips; for example, they can extend up to the tip of the sole, as isindicated by the broken line in FIG. 3. In this case, the production ofthe shoe sole is simplified.

All intermediate pieces 6, 11 are preferably formed in one piece so thata good cohesion is assured and manufacture is simplified. The productionof the shoe sole shown in FIG. 3 proceeds in the same way as theproduction of the shoe sole shown in FIGS. 1 and 2, with the differencethat the introduction of reinforcing layer 8 is dispensed with; thusonly upper sole part 1, proceeding from the under side of the same, ispartially separated for the formation of intermediate spaces, which takeup intermediate pieces 6, 11, so that even here a joining of the woodpiece can remain on the side laying opposite the under side, before thisis inserted into the mold.

What is claimed is:
 1. A shoe sole comprising an upper sole partcomprising wood, said upper sole part having an upper side which forms asupport for a sole of a foot and further having an underside, said shoesole further comprising a running sole of elastic and flexible materialarranged underneath said upper sole part, said upper sole part having aball region which is divided into a plurality of strips runningcrosswise to a longitudinal direction of said shoe sole, said stripsbeing joined together by flexible intermediate pieces, said shoe solefurther comprising a reinforcing layer which is rigidly joined to theunder side of said upper sole part in the ball region thereof.
 2. In theshoe sole of claim 1, said upper sole part being orthopedically shaped.3. In the shoe sole of claim 1, said flexible intermediate piecescomprising polyurethane.
 4. In the shoe sole of claim 1 said reinforcinglayer comprising at least one layer of wood veneer attached to the underside of said upper sole part.
 5. In the shoe sole of claim 4, said uppersole part having wood fibers running in the longitudinal direction ofthe sole, said at least one layer of said wood veneer having wood fiberswhich run perpendicular to the longitudinal direction of the wood fibersof the upper sole part.
 6. In the shoe sole of claim 1, said reinforcinglayer comprising a plastic layer which is attached to the under side ofthe upper sole part.
 7. In the shoe sole of claim 6, said plastic layercomprising a plastic foil.
 8. In the shoe sole of claim 6, said plasticlayer comprising a hardenable plastic material.
 9. In the shoe sole ofclaim 1, said reinforcing layer comprising a textile material attachedto the under side of said upper sole part.
 10. In the shoe sole of claim9, said textile material being reinforced with plastic.
 11. In the shoesole of claim 1, said reinforcing layer being rigidly attached only tothe under side of said wood strips and said under side of said woodupper sole part.
 12. A shoe sole comprising an upper sole partcomprising wood, said upper sole part having an upper side which forms asupport for a sole of a foot and further having an underside, said shoesole further comprising a running sole of elastic and flexible materialarranged underneath said upper sole part, said upper sole part having aball region which is divided into a plurality of strips runningcrosswise to a longitudinal direction of said shoe sole, said stripsbeing joined together by first flexible intermediate pieces, said stripsbeing divided into at least two parts whose front surfaces adjacent toone another run substantially in the longitudinal direction of the sole,said strip parts being joined together by second flexible intermediatepieces.
 13. In the shoe sole of claim 12, said upper sole part beingorthopedically shaped.
 14. In the shoe sole of claim 12, said flexibleintermediate pieces comprising polyurethane.
 15. In the shoe sole ofclaim 12, said first and second flexible intermediate pieces beingformed as an integral unit.
 16. In the shoe sole of claim 12, said firstand second flexible intermediate pieces and said running sole beingformed as an integral unit.
 17. A process for the production of a shoesole comprising the steps of:rigidly joining a reinforcing layer in aball region on an underside of an upper sole part consisting of wood;producing a plurality of cuts in the ball region on the underside ofsaid upper sole part, said cuts running crosswise to a longitudinaldirection of said sole, said cuts extending through said reinforcinglayer and substantially through said upper sole part wherein said uppersole part remains at least partially joined by wood material on an upperside of said upper sole part; introducing said upper sole part into amold; introducing a flexible liquid plastic into said mold so as to formflexible intermediate pieces in said cuts and to form a flexible runningsole arranged on the under side of said upper sole part; allowing saidplastic to solidify whereby said flexible intermediate pieces and saidrunning sole comprise an integral unit; and removing said sole from saidmold.
 18. The process of claim 17 further comprising the step ofremoving said wood material on said upper side of said upper sole partso as to form strips of wood material which are joined by flexibleintermediate pieces.